Machine for Making a Continuous Wall in the Ground

ABSTRACT

The machine for making a continuous wall in the ground comprises a rear portion having means for filling the portion of trench located behind the machine with concrete; a front portion having cutter means for making a portion of trench in front of the machine; and means for modifying the distance between said front and rear portions in a horizontal direction. The machine is characterized in that said cutter means include vertical guide means, at least one rotary cutter having an axis of rotation that is horizontal and parallel to the width of the trench, and means for moving said cutter along the guide means between a bottom position corresponding to the bottom of the trench and a top position disposed above the trench, said cutter being suitable both for cutting the ground of the trench and for kneading it in order to obtain a material in the pasty state.

This is a 371 national phase application of PCT/FR2006/050941 filed 25Sep. 2006, claiming priority to French Patent Application No. FR 0509956filed 29 Sep. 2005, the contents of which are incorporated herein byreference.

FIELD OF THE INVENTION

The present invention relates to a machine for making a continuous wallin the ground, and to a method of making such a wall.

BACKGROUND OF THE INVENTION

To make continuous walls in the ground, the technology that is mostcommonly used consists in digging a trench corresponding to the path ofthe wall that is to be made, and filling the trench with concrete,possibly together with reinforcement. More precisely, the trench isusually made in successive sections, with a dug section of trench thenbeing filled with concrete to constitute a panel of the continuous wall.

When the depth of the wall that is to be made is not very great, it ispossible to use an excavator machine that is moved along the trench asthe various sections of the trench are made.

U.S. Pat. No. 3,893,302 describes a machine and a method of excavatingtrenches and constructing walls in the excavated trenches. The machinecomprises a cutter tool disposed in the front portion of the machine,which tool is in the form of an endless excavator chain carryingbuckets. The rear portion of the machine has a vertical duct fordelivering concrete from a container situated outside the trench tobehind the machine so as to fill the trench that has just been dug.

That machine presents a certain number of drawbacks, and in particularfrom the fact that the continuous bucket chain does not enable thetrench to be extracted in all types of terrain, in particular such acutter tool cannot be used in hard terrain. It is known that certaintrenches need to be made in geological layers of differing hardnesses.

SUMMARY OF THE INVENTION

A first object of the present invention is to provide a machine formaking continuous walls in the ground and that remedies theabove-mentioned drawbacks.

To achieve this object, the machine for making a continuous wall in theground comprises:

-   -   a rear portion comprising:        -   first anchor means for anchoring in the side walls of the            trench; and        -   means for filling the portion of the trench located behind            the machine with concrete;    -   a front portion comprising:        -   second anchor means for anchoring in the side walls of the            trench;        -   cutter means for making a portion of trench in front of the            machine;        -   extractor means for extracting the ground cut away by the            cutter means; and    -   means for modifying the distance between said front and rear        portions in a horizontal direction;

the machine being characterized in that said cutter means comprise:

-   -   vertical guide means;    -   at least one rotary cutter having an axis of rotation that is        horizontal and parallel to the width of the trench; and    -   means for moving said cutter along the guide means between a        bottom position corresponding to the bottom of a trench and a        top position disposed above the trench, said cutter being        suitable both for cutting the ground of the trench and for        kneading it in order to obtain a material in the pasty state.

It will be understood that by using a cutter having its axis of rotationhorizontal and perpendicular to the length of the trench, the cutter canindeed be fitted with tools that are capable of passing through all ofthe layers of terrain that are conventionally present in building sites.Such cutter tools can be constituted by cutter picks.

In addition, during its upward and downward movements along the fullheight of the trench, the cutter acts not only to cut the ground, butalso to knead it together with the water that is usually naturallypresent in the ground. This produces a material in the pasty state thatcan subsequently be extracted easily.

In some circumstances, it is desirable to inject materials duringdigging, in particular if the quantity of water that is already presentis not sufficient for obtaining the pasty state. Such materials may bemud, with or without polymer, and also ground conditioning additives formodifying its consistency and/or its permeability.

Another object of the invention is to provide a method of makingcontinuous walls in the ground making use particularly but notexclusively of the above-described excavator machine.

The method of making a continuous wall in the ground comprises the stepsof:

-   -   digging a trench in the ground in successive sections with the        help of a machine that moves horizontally in the trench;    -   extracting the ground corresponding to digging the successive        sections of the trench;    -   moving the machine in successive steps corresponding to the        sections of the trench; and    -   filling the section of trench located behind the machine with        concrete;

said method being characterized in that the digging of sections oftrench is performed by vertically moving a rotary tool suitable both forcutting the ground in the trench and for kneading the ground cuttings inthe trench in order to transform them into a material in the pastystate.

Other characteristics and advantages of the invention appear better onreading the following description of various embodiments of theinvention given as non-limiting examples.

BRIEF DESCRIPTION OF THE DRAWINGS

The description refers to the accompanying figures, in which:

FIG. 1 is a perspective view showing the excavator machine as a whole,outside the wall and carried by a handling crane;

FIG. 2 is a perspective view showing the bottom portion of the excavatormachine;

FIG. 3 is a perspective view showing a preferred embodiment of means forextracting material in a pasty state;

FIG. 4 is a plan view of the bottom portion of the machine; and

FIG. 5 is a perspective view showing the machine as a whole while inuse.

DETAILED DESCRIPTION

FIG. 1 shows a handling crane comprising a platform 10 preferably fittedwith crawler tracks 12 and carrying a substantially vertical boom 14.This boom serves to support cables forming a pulley block 16 with theexcavator machine proper 18 being suspended from the bottom ends of thecables. The cutter tool of the excavator machine is a cutter 20 that isdescribed in greater detail below. The cutter 20 can be moved verticallyalong the structure of the excavator machine 18 with the help of acontrol bar 22 or “kelly”. The control bar 22 can be moved verticallywith the help of a winch on the handling crane. Reference 24 identifiesa structure for guiding the control bar 22 at the surface.

With reference more particularly to FIGS. 2 and 4, there follows adescription of a preferred embodiment of the excavator machine 18. It isconstituted by a front portion 26 and by a rear portion 28.

The front portion 26 comprises a structure constituting a vertical guidepart 29, a device for extracting ground cuttings 30, and preferablytubes for injecting a liquid additive into the cuttings, these tubesbeing referenced 32 and 34. The front portion 26 also has two series oftwo side shoes for anchoring in the side walls of the trench and givenrespective references 36 and 38. These shoes are controlled by actuators40. In the extended position, the shoes 36 and 38 press against thewalls 42 of the trench, thereby holding the front portion 26 of theexcavator machine stationary.

The rear portion 28 of the excavator machine is constituted essentiallyby a vertical structure 44 and by a pipe 46 for pouring concrete intothe section of trench that has been made. The rear portion 28 also hastwo sets of guide shoes 48 and 50 controlled by actuators 52. In theextended position, the shoes 48 and 50 form anchor means engaging theside walls 42 of the trench and thereby holding the rear portion 28 ofthe excavator machine 18 stationary.

The front portion 26 is also fitted with the cutter tool 20 mounted atthe bottom end of the control bar 22. The cutter tool is preferablyconstituted by a cutter comprising two drums 54 and 56 of horizontalaxis parallel to the width of the trench to be made. The cutter ismounted to rotate on a support 58 that is guided to move in translationby the guide part 29. The drums 54 and 56 are fitted with conventionalcutter picks 59.

In a variant embodiment, the cutter tool 20 constituted by the drums 54and 56 could be mounted on a support that is guided by the verticalguide 29, the support being fitted with a motor enabling the cutter tool20 to be moved in translation between a bottom position corresponding tothe bottom of the trench and a top position in which the cutter tool isdisposed above the trench.

The front and rear portions 26 and 28 of the excavator machine areinterconnected by at least two horizontally-acting actuators,respectively a bottom actuator 60 and a top actuator 62. These actuatorsserve to vary the horizontal distance between the front and rearportions 26 and 28 of the excavator machine and to apply thrust on thefront portion 26 of the excavator machine. This intermediate portion ofthe excavator machine is preferably also fitted with a system 64 forenabling the front and rear portions to take up a certain angle in ahorizontal plane. By way of example, this system can be constituted by acontrol actuator 66 mounted on the cylinder of the top actuator 62, thecontrol actuator 66 controlling a link 68 having one end secured to theend of the rod of the control actuator 66 and another end connected tothe structure of the front portion 26 of the excavator machine. A secondlink 70 co-operates with the first link 68 to constitute a deformableparallelogram. It can thus be understood that by controlling the controlactuator 66, it is possible to give a certain angle to the front portion26 of the excavator machine relative to its rear portion in a horizontalplane. Thus, it is possible to make a trench that is not rectilinear.Prior to imparting such an angle, the cutter tool 20 is caused to beraised so that it is located above the trench. This makes it easier toobtain an angle since the cutter tool does not oppose resistance totaking up an angle.

FIG. 3 shows a preferred embodiment of the system 30 for extractingcuttings. The extractor system is constituted by a cylindrical part 80of height not less than the height of the structure of the excavatormachine. Within this cylindrical part 80 an auger 82 is mounted torotate about a vertical shaft 84. The top portion of the part 80 has amotor 86 mounted thereon for turning the auger. The top end of the part80 also has an outlet for delivering the expected cuttings. Thecylindrical part 80 has a plurality of openings up its height such as 88that are of large dimensions so as to enable the cuttings for removal tobe placed on the auger 82.

Naturally, other cutting-extractor systems could be used, e.g. a bucketchain or a telescopic tube provided with a valve, or indeed a flexibletube flattened by wheels using the principle of peristaltic pumps, andproviding the means in question are not purely hydraulic.

The term extractor means that are not purely hydraulic is used herein tocover means that do not make use of the debris that results from theaction of the cutter tool being put into suspension in a liquid. Inparticular, the use of such extractor means is made possible by the factthat the ground cuttings are transformed into a material in the pastystate. The fact that debris is extracted without using large quantitiesof liquid considerably simplifies the processing of the spoil.

There follows a description of how the above-described machine is used,and thus of the method of the invention for making a continuous wall inthe ground.

A first section, constituting one panel having the depth of the work, ismade by using conventional means such as a cable bucket or a hydraulicbucket. The width of this first section of trench corresponds to thewidth dimension of the excavator machine. To ensure stability of theterrain, the panel is filled with mud.

The excavator machine 18 is then inserted into this section of trench,and then it is positioned so as to begin the horizontal digging process.For this purpose, the machine is initially held stationary by the frontactuators 36 and 38. The cutter tool 20 is caused to penetratevertically into the ground. As explained above, this cutter tool isconstituted by a cutter having drums that are driven, preferably by ahydraulic motor, the drums being provided with cutter picks.

The cutting capacity of such a tool is suitable for enabling it to passthrough all of the layers of terrain that are conventionally present onbuilding sites. During this descent stage, cuttings are not extracted.They are cut away and mixed with water present in the ground andpreferably also with materials injected by the pipes 32 and 34 duringdigging. These materials may be mud with or without polymer andground-conditioning additives for modifying its consistency and/or itspermeability. Thus, the drums serve not only to cut the ground in orderto make the trench, but also to knead the ground cuttings. Once thecutter tool 20 has reached the bottom, it may optionally change itsdirection of rotation and rise towards the surface. During the upwardand downward movements of the cutter tool, it acts not only to cut theground but also to knead the ground cuttings in order to transform theminto a material in the pasty state.

When a section of trench has been extracted and transformed intomaterial in the pasty state, the rear shoes 50 and 52 are put into theextended position in order to anchor the rear portion 28 of the machinein the trench, and the front shoes are retracted. Taking their reactionfrom the rear shoes, the horizontal actuators 60 and 62 apply thrust tothe front portion 26 of the excavator machine and in particular to thesystem 30 for extracting material in the pasty state. This thrustenables the extractor system to be fed through the openings 82. Theauger 84 then extracts the material in the pasty state.

In the following step, the front side shoes 36 and 38 are moved to theextended position in order to anchor the front portion 26 of theextractor machine, and the rear shoes are retracted. The horizontalactuators 60 and 62 are retracted so as to cause the rear portion 28 tomove closer to the front portion 26, thereby releasing a section oftrench behind the machine. This section of trench is filled immediatelywith concrete or with other materials suitable for this kind of workwith the help of the concreting system 46. It will be understood thatduring the concreting operation, while the excavator machine is heldstationary by its front shoes, it is possible to restart the diggingstage with the help of the cutter tool 20 so as to make a new section oftrench.

The cutting front of the trench is supported by the cutter tool 20bearing against the terrain in the pasty state. Lateral support can beprovided by a biodegradable fluid exerting hydrostatic pressure on thelimited volume of the thrust module.

It is also possible to verify that the excavator machine is vertical.The top and bottom pairs of thrust shoes respectively in the frontportion 26 and in the rear portion 28 of the excavator machine make itpossible to ensure that the structure of the machine is indeed in avertical position. Such position monitoring is performed prior toinserting the cutter tool for the purpose of making the next section oftrench. Any error in verticality can be corrected by actingappropriately on the various front & rear, and bottom & top shoes.

In addition, as mentioned above, the excavator machine preferablyincludes a system 64 for enabling a certain angle to be imparted in ahorizontal plane between the front and rear portions 26 and 28 of theexcavator machine. This makes it possible to make a trench that is notrectilinear, or on the contrary, when making a rectilinear trench, tocorrect for any horizontal path error.

1. A machine for making a continuous wall in the ground, the machinecomprising: a rear portion comprising: a first anchor device foranchoring in the side walls of the trench; and a device for filling theportion of the trench located behind the machine with concrete; a frontportion comprising: a second anchor device for anchoring in the sidewalls of the trench; a cutter device for making a portion of trench infront of the machine comprising a vertical guide device, at least onerotary cutter having an axis of rotation that is horizontal and parallelto the width of the trench; and a device for moving said cutter alongthe guide device between a bottom position corresponding to the bottomof a trench and a top position disposed above the trench, said cutterbeing suitable for cutting the ground of the trench and for kneading itin order to obtain a material in the pasty state; an extractor apparatusfor extracting the ground cut away by the cutter device; and a devicefor modifying the distance between said front and rear portions in ahorizontal direction.
 2. A machine according to claim 1, wherein saidfront portion further comprises an injector device for injecting aliquid additive into the ground cuttings in order to facilitateobtaining material in a pasty state.
 3. A machine according to claim 1,wherein said cutter is mounted on a support that is constrained to movealong a vertical guide device, said support being moved with the help ofa vertical control bar.
 4. A machine according to claim 3, wherein saidcontrol bar is moved by means of a winch of a handling crane.
 5. Amachine according to claim 1, wherein said cutter is mounted on asupport constrained to move along a vertical guide device, said supportbeing fitted with a motor apparatus.
 6. A machine according to claim 1,wherein said device for extracting material in the pasty state is adevice that is not purely hydraulic.
 7. A machine according to claim 6,said extractor apparatus comprises a hollow cylindrical part extendingsubstantially along the entire height of the trench and pierced withopenings facing towards the front of the machine, together with avertical-axis auger mounted in said cylindrical part.
 8. A machineaccording to claim 7, wherein said device for modifying horizontaldistance is suitable for applying thrust to the front portion of themachine when said first anchor device is activated.
 9. A machineaccording to claim 1, further comprising a device for imparting an anglein a horizontal plane between the front and rear portions of themachine.
 10. A method of making a continuous wall in the ground, themethod comprising the steps of: digging a trench in the ground insuccessive sections with the help of a machine that moves horizontallyin the trench; extracting the ground by digging the successive sectionsof the trench; moving the machine in successive steps corresponding tothe sections of the trench; and filling the section of trench locatedbehind the machine with concrete; wherein each of the trench sections isdug by moving a rotary tool solely in a vertical direction, which rotarytool is suitable, during vertical downward movement, for cutting theground in the trench, and during both the vertical downward movement andthe vertical upward movement of the rotary tool, for kneading the cutground in the trench in order to transform it into a material in thepasty state.
 11. A method according to claim 10, wherein an additive isinjected into the ground cuttings in order to facilitate obtaining thematerial in the pasty state.
 12. A method according to claim 10, whereinthe cutter tool is a rotary cutter having an axis of rotation that isorthogonal to the travel direction of the machine, said cutter beingmoved vertically.
 13. A method according to claim 10, wherein thematerial in the pasty state is extracted from the trench with the helpof a system that is not purely hydraulic and that is mounted on themachine.
 14. A method according to claim 10, wherein forward thrust isexerted with the help of a machine for maintaining the cutting front ofthe trench.
 15. A method according to claim 10, wherein a certain angleis imparted in a horizontal plane between the front and rear portions ofthe excavator machine in order to make a trench that is not rectilinear.